Recently, the demand for high-resolution and high-quality images has increased in various applications. However, as the resolution and quality of images become higher, the amount of information about the images also increases. Therefore, when image information is transmitted by using a medium such as an existing wired or wireless broadband line, or when image information is stored by using an existing storage medium, information transmission cost and information storage cost increase.
High-efficiency image compression technology may be used for effectively transmitting or storing and reproducing information of high-resolution and high-quality images.
In order to increase the efficiency of image compression, a method of predicting a current block by using information of neighboring blocks of the current block without directly transmitting information of the current block may be used.
As the prediction method, inter prediction and intra prediction may be used. In the inter prediction method, a pixel value of a current picture is predicted by referring to information of another picture. In the intra prediction method, a pixel value is predicted by using a correlation between pixels in the same picture. In the case of performing the inter prediction, it is possible to utilize information indicating a reference picture and information indicating a motion vector from neighboring blocks in an inter prediction mode so as to designate a portion to be used for prediction in another picture.
An encoding apparatus entropy-encodes image information including a prediction result and transmits the entropy-encoded image information as a bitstream, and a decoding apparatus entropy-decodes the received bitstream and reconstructs the image information.
The compression efficiency of image information may be increased through the entropy encoding and the entropy decoding.